The Republican presidential primary in South Carolina captures the news, but too little attention has been paid to the state itself. South Carolina reflects the triumph of Dr. Martin Luther King and the civil rights movement: Its schools are desegregated; its public facilities open to all, its economy benefits from foreign investment; its governor is a female Asian-American.

But South Carolina also reflects the limits of that victory and the continuing reaction against it. South Carolina shows how far we have to go.

Last month, the Justice Department, enforcing the Voting Rights Act, rejected as discriminatory South Carolina’s efforts to suppress the vote by requiring voters to show a driver’s license or other limited official forms of photo ID. Republicans are pushing these laws in states across the country. They claim they are needed to deter voting fraud, but offer no evidence of its existence. In fact, the laws will disproportionately impact African Americans, Latinos and poor people — who are less likely to have a driver’s license. In South Carolina, the DOJ concluded minority voters would be 20 percent more likely to be disenfranchised than white voters. Now, South Carolina plans to appeal the decision, seeking a Supreme Court decision overturning parts of the Voting Rights Act, Dr. King’s proudest triumph.

An anti-union state, South Carolina adds to the “race to the bottom” by offering employers cheap captive prison labor. The largest dairy farm in the state will be in a prison. The state aggressively markets its Prison Industries program to private employers, offering to “lease” prisoners or allow businesses to open branches within prison gates.

According to the state Department of Corrections, in one program, prisoners making desks and other office equipment for public agencies can make “a wage of up to 35 cents an hour.” In another program, the state negotiates with private customers, and prisoners earn from 35 cents to $1.80 an hour. And in the Prison Industry Enterprise Program, inmates produce goods for private employers ranging from apparel to cable wires. They are supposed to be paid the “prevailing wage,” and to not compete with private workers. They are allegedly paid from $5.15 to $10 per hour, but must pay for their “room and board,” and have up to 20 percent of their wages confiscated to repay their victims.

The next time you attend a graduation, remember that the gowns worn by the graduates are likely to have been made by South Carolina prison labor. The main gown plant of Jostens, a Fortune 400 company that is the largest manufacturer of graduation gowns in the country, is in Laurens, about 25 miles from the Leath Correctional Facility, a 350-bed prison for women.

According to Josh Levine in a 1999 Perspective magazine article, electronic-cable supplier Escod Industries abandoned plans for a facility in Mexico and moved to South Carolina. The wages of South Carolina prisoners undercut those of Mexican sweatshop workers, and the state offered to subsidize equipment and industrial space.

South Carolina is a leader in this area, but not alone. The U.S. locks up more than 2 million people, more than any nation in the world. One in 48 working-age men is behind bars. A disproportionate number — 40 percent — are African Americans. As Michelle Alexander reported in her book, The New Jim Crow, more black men are in prison or jail, on probation or parole than were in slavery in the 1850s.

The arc of history, Dr. King argued, is long but it bends towards justice. But as South Carolina illustrates, that bending requires constant struggle. We’ve come so far, but we’ve a long way to go.